How bubble deck technology is used in construction work

Bubble Deck belongs to the original combination method of connecting air, steel and concrete in two-way structural slab. Hollow plastic balls is embedded into the slab and reinforced with steel. The end result eliminates up to 35% of concrete that contains carrying effect at the time of restoring the two-way span strength. It can be used with most of the buildings particularly open floor design : educational, commercial, hospital and other organizational buildings.

Bubble Deck contains the following properties :-

Shear strength - 80% of solid deck slab
Deflection - Similar to solid slab
Weight - 40% below solid slab
Fire Resistance – 65% of solid slab

Bubble Deck slab belongs to a biaxial voided concrete slab in which high density polythene hollow sphere substitute the incompetent concrete in the middle of concrete slab.

Materials for building up the bubble deck

Steel: The steel reinforcement of MS or HYSD is applied.

Plastic Sphere: Void sphere formed with recycled high density polyethylene. It contains adequate strength & rigidity. It does not make any reaction.

Concrete: The concrete is formed with standard Portland cement with highest aggregate size of ¾ inch.

Bubble Deck Manufactured Components: It stands for a structural vacuumed smooth slab system that reduces dead weight of a floor slab by 33% facilitating longer span among column supports and forms an entire range of other cost and construction benefits.

The system acts as an alternative of all other supporting structure like beams or walls. The entire floor slab extents in two directions directly into pre-cast or in-situ reinforced concrete column.

Benefits of Bubble Deck:

Structural:
a. Less weight
b. No beams are necessary
c. Only few columns are essential
d. Make your choice for shape
e. Bigger Span

Construction
a. Fewer work on job site
b. Light weight, less equipment is necessary
c. Simple and does not require heavy jobsite work

Economy:
a. Huge savings for materials (slabs, beams, columns, foundation), up to 50%
b. Needs fewer carrying cost
c. Requirement of concrete is reduced up to 35%
d. Lower workforce, no carpentry, no beams and workers with less skill can be employed

Environmental:
a. Less material consumption (cement, aggregate, steel)
b. Less energy consumption (throughout production, transportation and lifting on construction site)



Read more
~~~~~~~~~~~~~~~~~~~~~~~~~~
Published By
Rajib Dey
www.constructioncost.co
~~~~~~~~~~~~~~~~~~~~~~~~~~

A new Roof-Top units is added with previous Steel Roof Structure

A right amount of experience is needed to know the exact problem of existing Steel roof structure before adding a new Roof top unit with it as the work needs experienced methods to do.

Often contractors are asked to calculate a previous steel roof structure to establish if it can support new roof top units or not. Often tenants remodel commercial spaces for their needs and also sometime new air make-up units, exhaust fans and HVAC units need to add.

What is Roof Top Unit: A packaged rooftop unit or RTU is a kind of HVAC system that has all the components needed to supply conditioned air in one brief unit. Packaged rooftop units are naturally found in light and large commercial applications. They are very famous in the construction industry with retail and industrial properties.

The Roof-top Unit or Roof Top Air Handling Unit supplies Heating, Ventilation, and Air Conditioning (HVAC) to the space below. Air duct Smoke Detectors or Duct Detectors can be inside the Roof Top Unit or in the air ducts below it.

In this article we are going to show evaluations of two commercial spaces for new rooftop units; where one space was adding a commercial kitchen and needed new exhaust fans and air make-up unit while the other needed new cooling units to reverse all the extra heat that was coming.

New roof top units can be large and heavy and generally affect the existing roof structure; sp at first the existing roof structure is examined to know the size, space and span of the joists, location of bearing walls and girders and location of previous roof top units. Generally a typical commercial roof structure is constructed with steel bar joists which are mainly tagged by the manufacturer like Vulcraft who keep records of joists’ type to use in the projects. Next all the accurate measurements of the top and bottom flanges, the web members and the length of the joist has taken; besides all this contractors have to observe other parameters to make sure all new and previous load can be transferred to the supporting structure in the right way.

After that the ability of from the manufacturer is determined and/or is modeled as per its section properties which help the contractors to calculate the load carrying capacity of the steel joist. As previous joists don’t have a lot of extra load carrying capacity so they can be strengthened by welding steel rods and plates to the flanges. But it is always best to locate a new unit away from previous units and near the previous bearing wall or girder which will limit the amount of new load on the previous joints. So basically it is mandatory to examine a previous structure to know its strength and capacity and qualifying it accordingly the new one as it creates a good understanding of structural design as well as a wealth of knowledge of building construction.



Read more
~~~~~~~~~~~~~~~~~~~~~~~~
Published By
Rajib Dey
www.constructioncost.co
~~~~~~~~~~~~~~~~~~~~~~~~

How to calculate the self weight of the different structural elements

A building load belongs to a force that should be confronted by the house frame. The frame should be designed in an efficient manner to resist eight of these loads ranging from wind, earth, and snow devoid of catastrophic stress on the structure.

Given below, the detail calculation method of self weight for the structural components:

a. Beam: It is applicable to different types of shapes like rectangular/square/tee/trapezoid for measuring the weight.
Weight of member = cross section area of member x length of member x RCC density
Suppose, the width is taken as 0.3 m and depth is taken as 0.45 m for the beam section with 5 m clear length & material density = 25 kn/m3 (for RCC), the weight should be as follow :-
Weight of beam = (0.3 x 0.45) x 5 x 25 = 16.875 Kn
The above calculated weight of 16.875 Kn stands for the total weight that should be transformed into Uniformly Distributed Load (UDL) by dividing the total weight with member length.
UDL = 16.875/5 = 3.375 Kn/m

b. Column: While measuring the self-weight of a column, the terminology of member length should be converted to member height & the weight of column should be computed as point load only its conversion in UDL is not necessary.

c. Slab: For RCC slabs, the weight of roof slabs is employed as invariable pressure in Kn/m2. For making analysis, a 1 m x 1 m square section is taken into consideration & the volume of the RCC is measured & then the same is multiplied with the density for derivation of pressure in kn/m2.

Weight of slab = (1 x 1 x slab thickness) x RCC density

In the above formula as (1 x 1) doesn’t impact the estimate thus it can be further clarified as follow :-
Weight of slab = slab thickness x RCC density

If the thickness of the slab is 0.15 m, then the estimate is done as follows :-
Weight of slab = 0.15 x 25 = 3.75 Kn/m2

In the above estimate of RCC slab weight further supplementary load resulting from floor finishes should be generally taken into consideration for stone/cement floorings as 0.75 kn/m2 to 1.5 kn/m2.

The U-value unit is the inverse those of R-value:

Disposition of slab load on supporting beams: Based on the placement of the beams (square or rectangular) triangular or trapezoidal shape distribution is performed. As for instance, for a rectangular slab of 6 m x 4 m the longer side beams distancing among A-B & D-C will bear the load of related trapezoidal portion while the shorter span beams distancing among A-D & B-C will support weight of roof slab arise out of the related triangular region.

Load on 6 m span = area of trapezoid x thickness of slab x density
Load on 6 m span = 8 x 0.15 x 25 = 30 Kn = 30 / member length = 30/6 = 5 Kn/m
The above estimated load of 30 Kn can be again transformed to UDL of 5 kn/m by dividing it with member length.
Load on 4 m span = area of triangle x thickness of slab x density
Load on 4 m span = 4 x 0.15 x 25 = 15 Kn = 15 / member length = 15/4 = 3.75 Kn/m

To get more details, go through the following article civilengineeronline99.blogspot.com

~~~~~~~~~~~~~~~~~~~~~~~~
Published By
Rajib Dey
www.constructioncost.co
~~~~~~~~~~~~~~~~~~~~~~~~